FromSoftware has announced that a patch for Elden Ring Nightreign will add two-player co-op mode, called “Duo Expeditions”, allowing players to team up with one other friend on July 30th. This feature was previously overlooked and neglected by the developers but is now being added as a response to community feedback. The update also includes user interface improvements and cost remains at $39.99.
Source: https://www.theverge.com/news/713829/elden-ring-nightreign-two-player-support-patch